[infiniband] Provide a general mechanism for path record lookups

Generalise out the path record lookup code from IPoIB.

1 files changed, 221 insertions, 0 deletions

diff --git a/src/net/infiniband/ib_pathrec.c b/src/net/infiniband/ib_pathrec.c
new file mode 100644
index 000000000..89622d981
--- /dev/null
+++ b/src/net/infiniband/ib_pathrec.c
@@ -0,0 +1,221 @@
+/*
+ * Copyright (C) 2009 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stdint.h>
+#include <string.h>
+#include <byteswap.h>
+#include <errno.h>
+#include <gpxe/infiniband.h>
+#include <gpxe/ib_gma.h>
+#include <gpxe/ib_pathrec.h>
+
+/** @file
+ *
+ * Infiniband path lookups
+ *
+ */
+
+/** Number of path record cache entries
+ *
+ * Must be a power of two.
+ */
+#define IB_NUM_CACHED_PATHS 4
+
+/** A path record cache entry */
+struct ib_cached_path_record {
+	/** Infiniband device's port GID
+	 *
+	 * Used to disambiguate cache entries when we have multiple
+	 * Infiniband devices, without having to maintain a pointer to
+	 * the Infiniband device.
+	 */
+	struct ib_gid sgid;
+	/** Destination GID */
+	struct ib_gid dgid;
+	/** Destination LID */
+	unsigned int dlid;
+	/** Rate */
+	unsigned int rate;
+	/** Service level */
+	unsigned int sl;
+};
+
+/** Path record cache */
+static struct ib_cached_path_record ib_path_cache[IB_NUM_CACHED_PATHS];
+
+/** Oldest path record cache entry index */
+static unsigned int ib_path_cache_idx;
+
+/**
+ * Find path record cache entry
+ *
+ * @v ibdev		Infiniband device
+ * @v dgid		Destination GID
+ * @ret cached		Path record cache entry, or NULL
+ */
+static struct ib_cached_path_record *
+ib_find_path_cache_entry ( struct ib_device *ibdev, struct ib_gid *dgid ) {
+	struct ib_cached_path_record *cached;
+	unsigned int i;
+
+	for ( i = 0 ; i < IB_NUM_CACHED_PATHS ; i++ ) {
+		cached = &ib_path_cache[i];
+		if ( memcmp ( &cached->sgid, &ibdev->gid,
+			      sizeof ( cached->sgid ) ) != 0 )
+			continue;
+		if ( memcmp ( &cached->dgid, dgid,
+			      sizeof ( cached->dgid ) ) != 0 )
+			continue;
+		return cached;
+	}
+
+	return NULL;
+}
+
+/**
+ * Resolve path record
+ *
+ * @v ibdev		Infiniband device
+ * @v av		Address vector to complete
+ * @ret rc		Return status code
+ */
+int ib_resolve_path ( struct ib_device *ibdev,
+		      struct ib_address_vector *av ) {
+	struct ib_gid *gid = &av->gid;
+	struct ib_cached_path_record *cached;
+	union ib_mad mad;
+	struct ib_mad_sa *sa = &mad.sa;
+	unsigned int cache_idx;
+	int rc;
+
+	/* Sanity check */
+	if ( ! av->gid_present ) {
+		DBGC ( ibdev, "IBDEV %p attempt to look up path record "
+		       "without GID\n", ibdev );
+		return -EINVAL;
+	}
+
+	/* Look in cache for a matching entry */
+	cached = ib_find_path_cache_entry ( ibdev, gid );
+	if ( cached && cached->dlid ) {
+		/* Populated entry found */
+		av->lid = cached->dlid;
+		av->rate = cached->rate;
+		av->sl = cached->sl;
+		DBGC2 ( ibdev, "IBDEV %p cache hit for %08x:%08x:%08x:%08x\n",
+			ibdev, htonl ( gid->u.dwords[0] ),
+			htonl ( gid->u.dwords[1] ), htonl ( gid->u.dwords[2] ),
+			htonl ( gid->u.dwords[3] ) );
+		return 0;
+	}
+	DBGC ( ibdev, "IBDEV %p cache miss for %08x:%08x:%08x:%08x%s\n", ibdev,
+	       htonl ( gid->u.dwords[0] ), htonl ( gid->u.dwords[1] ),
+	       htonl ( gid->u.dwords[2] ), htonl ( gid->u.dwords[3] ),
+	       ( cached ? " (in progress)" : "" ) );
+
+	/* If no unresolved entry was found, then create a new one */
+	if ( ! cached ) {
+		cache_idx = ( (ib_path_cache_idx++) % IB_NUM_CACHED_PATHS );
+		cached = &ib_path_cache[cache_idx];
+		memset ( cached, 0, sizeof ( *cached ) );
+		memcpy ( &cached->sgid, &ibdev->gid, sizeof ( cached->sgid ) );
+		memcpy ( &cached->dgid, gid, sizeof ( cached->dgid ) );
+	}
+
+	/* Construct path record request */
+	memset ( sa, 0, sizeof ( *sa ) );
+	sa->mad_hdr.base_version = IB_MGMT_BASE_VERSION;
+	sa->mad_hdr.mgmt_class = IB_MGMT_CLASS_SUBN_ADM;
+	sa->mad_hdr.class_version = IB_SA_CLASS_VERSION;
+	sa->mad_hdr.method = IB_MGMT_METHOD_GET;
+	sa->mad_hdr.attr_id = htons ( IB_SA_ATTR_PATH_REC );
+	sa->sa_hdr.comp_mask[1] =
+		htonl ( IB_SA_PATH_REC_DGID | IB_SA_PATH_REC_SGID );
+	memcpy ( &sa->sa_data.path_record.dgid, &cached->dgid,
+		 sizeof ( sa->sa_data.path_record.dgid ) );
+	memcpy ( &sa->sa_data.path_record.sgid, &cached->sgid,
+		 sizeof ( sa->sa_data.path_record.sgid ) );
+
+	/* Issue path record request */
+	if ( ( rc = ib_gma_request ( &ibdev->gma, &mad, NULL ) ) != 0 ) {
+		DBGC ( ibdev, "IBDEV %p could not get path record: %s\n",
+		       ibdev, strerror ( rc ) );
+		return rc;
+	}
+
+	/* Not found yet */
+	return -ENOENT;
+}
+
+/**
+ * Handle path record response
+ *
+ * @v ibdev		Infiniband device
+ * @v mad		MAD
+ * @ret rc		Return status code
+ */
+static int ib_handle_path_record ( struct ib_device *ibdev,
+				   union ib_mad *mad ) {
+	struct ib_path_record *path_record = &mad->sa.sa_data.path_record;
+	struct ib_gid *dgid = &path_record->dgid;
+	struct ib_cached_path_record *cached;
+	unsigned int dlid;
+	unsigned int sl;
+	unsigned int rate;
+
+	/* Ignore if not a success */
+	if ( mad->hdr.status != htons ( IB_MGMT_STATUS_OK ) ) {
+		DBGC ( ibdev, "IBDEV %p path record lookup failed with status "
+		       "%04x\n", ibdev, ntohs ( mad->hdr.status ) );
+		return -EINVAL;
+	}
+
+	/* Extract values from MAD */
+	dlid = ntohs ( path_record->dlid );
+	sl = ( path_record->reserved__sl & 0x0f );
+	rate = ( path_record->rate_selector__rate & 0x3f );
+	DBGC ( ibdev, "IBDEV %p path to %08x:%08x:%08x:%08x is %04x sl %d "
+	       "rate %d\n", ibdev, htonl ( dgid->u.dwords[0] ),
+	       htonl ( dgid->u.dwords[1] ), htonl ( dgid->u.dwords[2] ),
+	       htonl ( dgid->u.dwords[3] ), dlid, sl, rate );
+
+	/* Look for a matching cache entry to fill in */
+	if ( ( cached = ib_find_path_cache_entry ( ibdev, dgid ) ) != NULL ) {
+		DBGC ( ibdev, "IBDEV %p cache add for %08x:%08x:%08x:%08x\n",
+		       ibdev, htonl ( dgid->u.dwords[0] ),
+		       htonl ( dgid->u.dwords[1] ),
+		       htonl ( dgid->u.dwords[2] ),
+		       htonl ( dgid->u.dwords[3] ) );
+		cached->dlid = dlid;
+		cached->rate = rate;
+		cached->sl = sl;
+	}
+
+	return 0;
+}
+
+/** Path record response handler */
+struct ib_mad_handler ib_path_record_handler __ib_mad_handler = {
+	.mgmt_class = IB_MGMT_CLASS_SUBN_ADM,
+	.class_version = IB_SA_CLASS_VERSION,
+	.method = IB_MGMT_METHOD_GET_RESP,
+	.attr_id = htons ( IB_SA_ATTR_PATH_REC ),
+	.handle = ib_handle_path_record,
+};